I uploaded a new version of Number Mnemonic today to Apple. I expect it will be available on the app store in a few days.
This version includes some new user interface bits restricting it to iPhone OS 3.0 or later. Instead of a tab based interface, it now flips between front and back.
A "Fast Mode" was also to the search algorithm. Fast Mode ignores any word more than five letters long. This speeds up the searches significantly making Number Mnemonic an effective party app.